Coupling dynamo-electric machines



E. THOMSON. COUPLING DYNAMO ELBGTRIG MACHINES.

N0. 36Z,866. Patented Aug. 9, 1887'.

A TTORNE Y UNITED STATES PATENT OFFICE ELIHU THOMSON, OF LYNN,MASSACHUSETTS.

COUPLING DYNAMO-ELECTRIC MACHINES.

SPECIFICATION forming part of Letters Patent No. 367,866, dated August9. 1 7.

Application tiled June 4, 1386. Serial Nam-1,129. (No model.)

To all whom it may concern:

Be it k now u that I, ELIHU THOMSON, a citizen 0f the United States, anda resident of Lynn, in the county of Essex andState of Massachusetts,have invented certain new and useful Improvements in Coupling Dynamo-Machines, of which the following is a specification.

My invention relates to dynamo-electric inachines coupled in multiplearc to an electric circuit.

My invention is designed especially for application to dynamo-machineswhen coupled in multiple arc, and at the same time provided with anequalizirig-connection, such as described in the patent of E. \V. Rice,No. 328,253, dated October 12, 1885.

The object of my invention is to prevent the injury which would resultfrom the slipping of the driving-belt for one armature; and to this endtheinvention consistsin placing a fusible plug in the connection fromeach armature to the outside circuit or main, such plug being located ata point between the armature and the pointwhere theequalizing-connection between the two arinatures is made.

My invention is shown as applied to the case 01' compound wounddynamomachines.

The drawing illustrates the invention diagrammatically.

The arniatures of the two machines are indicated at A A, respectively,and their derived circuit field-coils are indicated at S S,respectively.

D D indicate the direct-circuit field-coils, and E theequalizing-eonneetion, which connection is a low-resistance wire joiningthe maehinecircuits between their armatures and their direct-fieldcoils.

M M are the mains to which the dynamos are coupled in multiple are, andL the incandescent lamps or other translating devices.

The plugs P P are inserted in the circuit between the armature and thefield-magnet coils, as shown.

The equalizer is connected at a point between the fleld-magnet coils andthe plugs or safety-catches.

If the beltdriving one armature, A, should slip oil, or theelectromotive l'oreeof Ashould fall off greatly from any other cause, ashort circuit would be formed from armature A through 1 E P, armature A,and back to A to connection I). The plugs P 1, one or both, would thenmelt and interrupt the short circuit formed, thus saving both armaturesfrom injury.

What I claim as my invention is- The combination, with compound wounddynamo-machines connected in multiple are, and provided with anequalMing-connection, as described, of fusible plugs or salety-catcheslocated between the armatu res and the equalizing-connection.

Signed at Lynn, in the county of Essex and State of Massachusetts, this28th day of May, A. D. 1886.

ELIHU THOMSON.

lVilnesses:

M. L. THOMSON, N. M. HAwKEs.

